CN101373198B - Cable test bus and switch matrix circuit - Google Patents
Cable test bus and switch matrix circuit Download PDFInfo
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- CN101373198B CN101373198B CN2007101204913A CN200710120491A CN101373198B CN 101373198 B CN101373198 B CN 101373198B CN 2007101204913 A CN2007101204913 A CN 2007101204913A CN 200710120491 A CN200710120491 A CN 200710120491A CN 101373198 B CN101373198 B CN 101373198B
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- 238000012360 testing method Methods 0.000 title claims abstract description 63
- 239000011159 matrix material Substances 0.000 title claims abstract description 22
- 239000000463 material Substances 0.000 abstract description 4
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- 238000005259 measurement Methods 0.000 abstract 1
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Abstract
The invention relates to a cable testing bus and a switching matrix circuit. The cable testing bus consists of a differential line pair and a double-pole-double-throw switch; the moving contact and the normally closed contact of the switch are connected on the differential line pair; the switching matrix circuit takes the cable testing bus as a main signal path, and comprises two transformers andfour cable testing buses; and the coaxial end of the transformer is connected with the port of a testing apparatus, and the symmetrical end of the transformer is connected with the cable testing bus.The switching matrix circuit is characterized by cutting material cost, minimizing odds of testing equipment failure and reducing workload of nonstop calibration. The cable testing bus has the advantages that normal isolation from objective can be realized and the length of the cable testing bus can be controlled on the spot. Furthermore, the cable testing bus has sufficient bandwidth and constant characteristic resistance, and keeps working in matching condition, thereby ensuring measurement accuracy.
Description
Technical field
The present invention relates to a kind of measuring system circuit and signal main channel thereof, the especially a kind of cable test bus and switch matrix circuit that can reduce number of devices, quickening calibration speed, reduce equipment failure.
Background technology
All use network analyzer as survey instrument in symmetrical cable (or other balancing components) test macro, network analyzer is a coaxial port, during test balance object, needs to use transformer to finish imbalance/balance conversion, finishes the test target conversion with on-off circuit.At present, the on-off circuit that adopts is " hilted broadsword is thrown (SPNT) more " formula coaxial type on-off circuit both at home and abroad, its structure is a star, because general " single-pole double-throw (SPDT) " switch that adopts can only constitute SPNT, " SPNT " formula coaxial type on-off circuit by the method for switch cascade when tested cable is many logarithms, be to do coaxial branch earlier, carry out changing again with rotational symmetry, so transformer is installed in after the branch, before the terminal, therefore, the quantity of transformer is the twice of tested number of cable.For example: the test macro of 4 pairs of cables, need 8 principal invariant devices and more concentric cable, coaxial switch (seeing accompanying drawing 1), the line of each switch ends is concentric cable in the accompanying drawing 1, and respectively there is a pair of coaxial switch at the concentric cable two ends.When tested number of cable increased, the number of required transformer and concentric cable, coaxial switch because the transformer cost is higher, will increase equipment cost from also increasing like this, and table 1 is a material usage of adding up " SPNT " formula on-off circuit scheme roughly.
| ? | Transformer | Concentric cable | Coaxial switch |
| 4 pairs of test macros | 8? | 24+4? | 56? |
| 50 pairs of test macros | 100? | ＞300+4? | ＞500? |
Table 1
From accompanying drawing 1 as can be seen, each test comprises different two principal invariant devices and different paths, because the performance of each transformer can not be accomplished unanimity, therefore the different transformer of each process all needs to carry out once straight-through calibration, again 4 select the normal opened contact of 1 switch different with the decay of normally closed contact (seeing accompanying drawing 2) causes the insertion decay in each path different, therefore the different path of each process all needs to carry out once straight-through calibration, that is to say, the calibration number of times of this type of scheme equals the total degree of every test, the calibration operation amount is very big, and tested demand pairs are big more, and the calibration number of times is many more, calibrate consuming time manyly more, reduce test speed; Increase along with tested demand pairs needs more switches, and the probability that the circuit control section breaks down is big more.
Summary of the invention
First aspect present invention provides a kind of cable test bus, as the signal main channel of the described switch matrix circuit of second aspect present invention.
First aspect present invention provides following technical scheme by some embodiment: a kind of cable test bus (CTB), comprise differential lines to the switch with dpdt double-pole double-throw (DPDT) (DPDT) function, the moving contact of described switch and normally closed contact are connected described differential lines to last.
First aspect present invention by some embodiment realized that CTB length scene is controlled, CTB and the target normality is isolated, CTB has constant characteristic impedance and the wideband test.
Second aspect present invention provides a kind of switch matrix circuit, in order to solve the problem that prior art exists, realizes that equipment cost reduces, the calibration operation amount reduces, equipment breaks down, and probability reduces.
Second aspect present invention provides following technical scheme by some embodiment: more than one state the switch matrix circuit that cable test bus is the signal main channel, comprise two transformers and four cable test bus, the same axle head of described two transformers connects two test macro ports respectively, and the symmetry end of described transformer connects described cable test bus.
CTB in the second aspect present invention by differential lines to constituting, therefore do not need coaxial connector in the switch matrix, only solved and to have connected a plurality ofly with two transformers, reduced the cost input of measuring equipment, reduced the probability that equipment breaks down by the right problem of survey line;
Because described two transformers are all passed through in each test, solved because the different problems of calibrating of all needing of transformer performance have reduced the calibration operation amount at every turn.
Second aspect present invention has realized that by some embodiment equipment cost reduction, calibration number of times reduce, equipment breaks down the purpose that probability reduces.
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
Description of drawings
Fig. 1 is prior art " SPNT " formula switch matrix circuit overall block-diagram;
Fig. 2 is prior art " SP4T " synoptic diagram;
Fig. 3 is a first aspect present invention embodiment synoptic diagram;
Fig. 4 is the synoptic diagram of second aspect present invention embodiment;
Fig. 5 is the electrical schematic diagram of second aspect present invention embodiment.
Embodiment
Fig. 3 is a first aspect present invention embodiment synoptic diagram.As shown in Figure 3, to forming, the moving contact of switch and normally closed contact are connected differential lines to last (not shown) to CTB by switch L111, L112, L113 and differential lines with dpdt double-pole double-throw (DPDT) function.
The build-out resistor that dots among Fig. 3 is used for the unloaded coupling of CTB, when CTB is used to test it is disconnected.
The normally opened contact linking objective of switch (comprising the normally opened contact of switch on another root cable test bus, tested cable) is isolated so target and CTB are normalities, for the impedance matching of CTB provides necessary condition;
Switch has the DPDT function, last certain switch of CTB is received the control signal action, its normally opened contact closure, it is right that target is connected differential lines, can make test signal only reach required target place and no longer lead in the following circuit, thus, the length of CTB bus is on-the-spot controlled, for the CTB impedance matching provides necessary condition;
When test, because CTB can only connect a pair of tested cable, the circuit below it disconnects, and provides necessary condition for CTB has constant characteristic impedance, has guaranteed measuring accuracy;
Described switch adopts high frequency relay, owing to the signal by relay can be a direct current signal, also can be high-frequency signal, therefore adopts relay can realize the wideband test of cable.
Fig. 4 is a second aspect present invention switch matrix circuit embodiment synoptic diagram.As shown in Figure 4, this switch matrix circuit comprises two transformers and four cable test bus, and the same axle head of transformer passes through the coaxial cable connectivity port, the symmetry end stube cable test bus of transformer, and this circuit structure is a rectangle.
In the present embodiment, four cable test bus have been formed two end menu unit, two straight-through alignment units, four pairs of measured target contiguous unit that link to each other with transformer symmetry end, end menu unit is used to select the port of signal access, straight-through alignment unit is used for straight-through calibration, and the measured target contiguous unit is used to connect tested cable.
Fig. 5 is a second aspect present invention switch matrix circuit embodiment electrical schematic diagram.As shown in Figure 5, this switch matrix circuit comprises that 10,20, four CTB of two transformers are L11, L12, L21, L22 from top to bottom;
The moving contact of switch L111, L112, L113 and normally closed contact are connected on the L11, the moving contact of switch L121, L122, L123 and normally closed contact are connected on the L12, the moving contact of switch L211, L212, L213 and normally closed contact are connected on the L21, the moving contact of switch L221, L222, L223 and normally closed contact are connected on the L22, the normally closed contact of switch L111 connects the moving contact of L112, the normally closed contact of L112 connects the moving contact of L113, and it is right that L111, L112, L113 divide differential lines equally;
L11, L21 be about port one and transformer 10 symmetries, and by port one to port 2 continuities, L12, L22 be about port 2 and transformer 20 symmetries, and continued to port one by port 2;
Switch L111, the normally opened contact of L211 is corresponding to link to each other, form end menu unit 11, the symmetry end of link variable device 10, switch L121, the normally opened contact of L221 is corresponding to link to each other, form end menu unit 21, the symmetry end of link variable device 20, switch L112, the normally opened contact of L122 is corresponding to link to each other, form straight-through alignment unit 12, switch L212, the normally opened contact of L222 is corresponding to link to each other, form straight-through alignment unit 22,4 couples of switch L113, the normally opened contact of L123 is corresponding to link to each other, form measured target contiguous unit 131 respectively, 132,133,134,4 couples of switch L213, the normally opened contact of L223 is corresponding to link to each other, and forms measured target contiguous unit 231 respectively, 232,233,234;
In order to increase isolation, between L113, the L123 or the normally opened contact between L213, the L223 can link to each other by double-point double-throw switch;
Measured target contiguous unit 131 and 231,132 and 232,133 and 233,134 and 234 is connected the head and the tail two ends of tested cable respectively, can test 4 pairs of cables among Fig. 5, all be connected with the electric wire connecting junction that is used to connect tested cable on each measured target contiguous unit, in order to simplify, only show the electric wire connecting junction (little box indicating) that links to each other with rightmost side measured target contiguous unit 134 among Fig. 5.
Because whole C TB is that differential lines is to structure, therefore do not need the coaxial connector among Fig. 1 in this switch matrix circuit, simultaneously, this switch matrix circuit only needs two transformers, irrelevant with tested number of cable, transformer links to each other with port by concentric cable with axle head, therefore only needs 2 concentric cable and 2 pairs of coaxial switches; The tested demand pairs of present embodiment are 4, compare with Fig. 1 of same tested number of cable, present embodiment only needs two transformers, and Fig. 1 needs 8, when the test cable number increases, structure shown in Figure 1 will need more transformer and coaxial component, therefore, present embodiment can significantly reduce the measuring equipment amount, and then reduce the probability that equipment cost and equipment break down, because equipment amount reduces, the Equipment Alignment workload also can reduce, and table 2 is material usages of rough Statistics CTB bus switch matrix circuit scheme;
| ? | Transformer | Concentric cable | Coaxial switch |
| 4 pairs of test macros | 2? | 2? | 2? |
| Many to test macro | 2? | 2? | 2? |
Table 2
The differential lines of every CTB is to being printed on the printed circuit board (pcb), calculate by little band, reach strictness control to PCB technology and pcb board material, at first finish the PCB design and the wiring of a unit (comprising elements such as one section CTB and relay), this unit can be called reference cell, then with reference cell as sample, finish other unit wiring on the monoblock pcb board with the method for duplicating (Copy), the electrical property of each unit in the assurance system thus, comprise impedance, insert decay, the isoparametric unanimity of time delay.
When inserting attenuation test, play first pair of measured target contiguous unit 131 as surveying a left side, insertion decay between 231: test signal is flowed into by the left side port, the normally opened contact of switch L111 is received on the cable test bus L11, it is 2 that test signal needs the CTB hop count of process via L111 to measured target contiguous unit 131, the normally opened contact of switch L221 is connected on the cable test bus L22, therefore test signal flows out from the right side port via switch L221, the CTB hop count that test signal need be passed through from measured target contiguous unit 231 to the right side port is 4, that is to say, survey the insertion decay between measured target contiguous unit 131 and the measured target contiguous unit 231, the CTB hop count that needs process is 6 (2+4), simultaneously, CTB hop count between straight-through alignment unit 12 and the left side port is 1, CTB hop count between straight-through alignment unit 22 and the right side port is 5, and the two sum also is 6 (1+5).When remaining measured target contiguous unit is inserted attenuation test, total CTB hop count of signal process still is 6, again because on same pcb board of CTB bus, finish circuit design in the mode of duplicating, and with little band calculating, PCB technology has guaranteed the accurate and consistance of each section impedance, therefore, can insert the decay calibration with method of substitution, and once finish and insert the straight-through calibration that decays, the straight-through calibration of also just saying all insertion decay can substitute by the straight-through calibration of the near-end of straight-through alignment unit 12 or straight-through alignment unit 22, with a plurality of path branches of Fig. 1, each path branches all will be inserted the calibration operation amount of the straight-through calibration of decay and compare, present embodiment has reduced to insert the straight-through calibration operation amount of decay greatly, because reducing of calibration number of times improved test speed undoubtedly.
It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (9)
1. cable test bus is characterized in that: comprise differential lines to the switch with dpdt double-pole double-throw (DPDT) function, the moving contact of described switch and normally closed contact are connected described differential lines to last.
2. cable test bus according to claim 1 is characterized in that: described switch is a relay.
3. cable test bus according to claim 1, it is characterized in that: described switch comprises the switch (L111) that is used to form end menu unit, the switch (L113) that is used to form the switch (L112) of straight-through alignment unit and is used to form the measured target contiguous unit, the moving contact that is used to form the switch (L111) of end menu unit connects the moving contact of the switch (L112) that is used to form straight-through alignment unit, the normally closed contact that is used to form the switch (L112) of straight-through alignment unit connects the moving contact of the switch (L113) that is used to form the measured target contiguous unit, and is used to form the switch (L111) of end menu unit, be used to form the switch (L112) of straight-through alignment unit, it is right that the switch (L113) that is used to form the measured target contiguous unit is divided differential lines equally.
4. cable test bus according to claim 3 is characterized in that: the described number that is used to form the switch (L113) of measured target contiguous unit is 1, perhaps is in sequential series more than 1.
5. according to the arbitrary described cable test bus of claim 1-4, it is characterized in that: the spacing unanimity between the adjacent described switch.
6. one kind is the switch matrix circuit of signal main channel with the described cable test bus of claim 1, it is characterized in that: comprise two transformers and four described cable test bus, the same axle head of described two transformers connects two testing tool ports respectively, and the symmetry end of described transformer connects described cable test bus.
7. switch matrix circuit according to claim 6, it is characterized in that: described cable test bus is formed two end menu units, two straight-through alignment units, at least one pair of measured target contiguous unit, one end of described two end menu units links to each other with the symmetry end of described two transformers respectively, the first end menu unit links to each other with an end of described two straight-through alignment units, the other end of described two straight-through alignment units links to each other with described at least one pair of measured target contiguous unit respectively, the second end menu unit links to each other with described at least one pair of measured target contiguous unit, and described at least one pair of measured target contiguous unit links to each other with described two straight-through alignment units respectively.
8. switch matrix circuit according to claim 7, it is characterized in that: first and second are used to form the switch (L111 of end menu unit, L211) normally opened contact is corresponding to link to each other, form the first end menu unit (11), the symmetry end that connects first transformer (10), third and fourth is used to form the switch (L121 of end menu unit, L221) normally opened contact is corresponding to link to each other, form the second end menu unit (21), the symmetry end that connects second transformer (20), first and second are used to form the switch (L112 of straight-through alignment unit, L122) normally opened contact is corresponding to link to each other, form the first straight-through alignment unit (12), third and fourth is used to form the switch (L212 of straight-through alignment unit, L222) normally opened contact is corresponding to link to each other, form the second straight-through alignment unit (22), first and second are used to form the switch (L113 of measured target contiguous unit, L123) normally opened contact is corresponding to link to each other, form the first measured target contiguous unit (13), third and fourth is used to form the switch (L213 of measured target contiguous unit, L223) normally opened contact is corresponding to link to each other, and forms the second measured target contiguous unit (23).
9. according to claim 7 or 8 described switch matrix circuits, it is characterized in that: first and second cable test bus (L11, L21) are about first transformer (10) symmetric arrangement, and continue to second port (2) that is connected with second transformer (20) by first port (1) that is connected with first transformer (10), third and fourth cable test bus (L12, L22) is about second transformer (20) symmetric arrangement, and by second port (2) that is connected with second transformer (20) to first port (1) continuity that is connected with first transformer (10).
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| CN2007101204913A CN101373198B (en) | 2007-08-20 | 2007-08-20 | Cable test bus and switch matrix circuit |
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| CN2007101204913A CN101373198B (en) | 2007-08-20 | 2007-08-20 | Cable test bus and switch matrix circuit |
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| CN101373198B true CN101373198B (en) | 2011-03-16 |
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| CN103809051B (en) * | 2012-11-13 | 2017-11-03 | 上海斐讯数据通信技术有限公司 | The detection method of switch matrix, Auto-Test System and switch matrix therein |
| CN103647120B (en) * | 2013-12-27 | 2015-05-13 | 成都芯通科技股份有限公司 | Switching matrix for testing combined type radio frequency power amplifier |
| CN105467169B (en) * | 2015-12-17 | 2018-03-06 | 中国民航大学 | Aero-engine electric attachments conduction measuring loop connection method |
| CN107817368B (en) * | 2017-09-27 | 2021-03-23 | 南京捷希科技有限公司 | Multi-channel S parameter measuring device and measuring method |
| CN113899952B (en) * | 2021-10-26 | 2023-07-28 | 西安微电子技术研究所 | Automatic impedance testing system and method |
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